1. Field of the Invention
This invention relates to improvements in ophthalmology and more particularly to improvements in artificial intraocular lenses (pseudophakoi) used for the correction of aphakia and re-establishment of binocularity in aphakia.
2. Discussion of the Prior Art
Well-fixed and well-centered intraocular lens implants are known to produce stable retinal images with stable space localization and offer the best chance of re-establishment of binocularity in cases of aphakia.
Many techniques of lens implantation, including suturing to the ciliary muscle as disclosed in U.S. Pat. No. 3,711,870 and iris diaphragm fixation as disclosed in U.S. Pat. No. 3,673,616 for example, have been used. The latter is considered to be a safe procedure giving good stability and the present invention deals with improvements in this general type of pseudophakos. More particularly, the invention relates to improvements in "iridocapsular" and/or "iris clip" implants having a fastening section comprised of posterior and/or anterior iris clips which may be in the form of loops or struts of wire or wire-like material.
Heretofore, iris clips have been fastened by extending ends thereof into holes drilled or otherwise formed in the lenses. Anchoring against accidental withdrawal and disconnection from the lens has, however, presented the serious problem of having to establish and maintain exacting tolerances of hole and wire size for fitting and/or the use and dependence upon cements.
The latter, in requiring adhesive materials which are biologically inert and resistant to absorption or deterioration by human body fluids, not to mention having to be strong bonding, leaves few materials to choose from and less than optimum product dependability. There is an attending possibility of subsequent deterioration of the bonded materials, if not the cement, causing loosening or detachment of parts in the eye.
Press fitting, on the other hand, which eliminates the additional material of cements but requires exacting tolerances of hole and wire size as already mentioned, presents exceptional manufacturing problems. The miniaturization of lenses and the wire size of clips and anchoring hole diameters required of pseudophakoi are alone problematic, not to mention compounding thereof by requirements for press fit tolerances. Tediousness and high scrap yield seriously limit production output and contribute to high, if not excessive, product cost, all without assurance that material erosion or decomposition will not occur to the extent of loosening or disconnection of parts under prolonged usage.
Additionally, all pseudophakoi require sufficient sturdiness of structure to withstand relatively harsh manipulation and adjustment of parts by the surgeon prior to and/or during implantation. Thus, an assurance against accidental disconnection of parts is urgently sought.
It is, accordingly, a principal object of the present invention to provide an improved pseudophakos and method of making same wherewith positive locking together of lens and iris clips may be accomplished relatively simply, quickly and economically to maximize manufacturing output, minimize product cost and provide both the surgeon and recipient with an assurance against disconnection of its parts.